As the technology and science continuously progress and the standard of living continuously rises, the automobile has been the primary transportation equipment in daily living and brings great convenience to people, and almost every family has at least one automobile now. However, owing to fast-increasing quantity of the automobiles, the streets are crowded with the automobiles; thus, in addition to that driving the automobile always has a crisis of collision, street parking also challenges the driver's skill because of the obstacles around the parking place or other automobiles before or behind the parking bay. Furthermore, some driver, whose driving skill is not sophisticated enough, cannot accurately estimate the distance between the automobile and the obstacles around the parking bay by visual observation, so that a scratch or collision will occur often, which puts a great strain on the driver, and besides the damage of the driver's own automobile, the driver has to reimburse the damage to another's automobile if the collision incurs a damage to another's automobile.
Thus, there is a manufacturer developing a device of back radar, wherein an infrared detector, or another sensor, is installed on the rear bumper or another portion of the automobile and a receiver is installed inside the driving compartment. When reversing the automobile, the detector A installed in the rear of the automobile, as shown in FIG. 1 and FIG. 2, can measure the distance between the automobile and the obstacles behind the automobile. When the distance is equal to or short than the preset value, the receiver inside the driving compartment will display and alarm to remind the driver to keep on reversing or to drive forward. Such a device can help the driver of a big vehicle or the driver lacking sophisticated skill to some extent; however it has the following drawbacks:
Firstly, the inner face the cover flange B1 of the head sleeve B of the conventional detector A is vertical, and the head sleeve B can only apply to a planar bumper and cannot apply to an upward-tilt or downward-tilt bumper; thus, the conventional detector cannot be assembled to various automobiles, and its utilization is limited.
Secondly, in the conventional detector A, the head sleeve B and the ultrasonic head C1 of the vehicle-reversing module C are coated separately before the ultrasonic head C1 is assembled to the device body; however, the appearance of the top portion of the ultrasonic head C1 will be muddled because of the previous coating, and the detecting face's paint of the ultrasonic head C1 cannot be concealed when the ultrasonic head C1 is further assembled into the head sleeve B; thus, additional coating is needed, and additional man-hour is spent thereon.
Thirdly, the head sleeve B and the vehicle-reversing module C are coated separately before assemblage; however, the paint on the surface of the ultrasonic head C1 is apt to be scratched when the ultrasonic head C1 is assembled into the head sleeve B, which needs additional coating step and lowers the efficiency of assemblage; furthermore, the workshop cannot rapidly assemble the ultrasonic head with the device body and the head sleeve B via preparing multiple ultrasonic heads C1 to meet the demand of the consumer; thus, the assemblage thereof is slow and time-consuming.